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At least 19 records

Assessment of Coated Particle Fuels for Space Nuclear Power and Propulsion Systems: A Report for the NESC Nuclear Power & Propulsion Technical Discipline Team

This study evaluates terrestrial reactor fuel forms, with an emphasis on the coated particle fuel capability under development by interagency reactor programs, for application to space reactor systems of interest to NASA. A comprehensive review of coated particle fuel readiness and qualification status has been performed. Possible derivative fuel forms based on coated particle fuel manufacture technologies are identified and assessed for fission surface power, nuclear electric propulsion, and nuclear thermal propulsion systems. Assessments for terrestrial coated particle and historic fuels were compared for each system allowing for relative risk and common fuel qualification needs to be identified.

Fission Surface Power

Multimegawatt nuclear power systems for nuclear electric propulsion

Results from systems analysis studies of multimegawatt nuclear power systems are presented for application to nuclear electric propulsion. Specific mass estimates are presented for nearer term SP-100 reactor-based potassium Rankine and Brayton power systems for piloted and cargo missions. Growth SP-100/Rankine systems were found to range from roughly 7 to 10 kg/kWe specific mass depending on full power life requirements. The SP-100/Rankine systems were also found to result in a 4-kg/kWe savings in specific mass over SP-100/Brayton systems. The potential of advanced, higher temperature reactor and power conversion technologies for achieving reduced mass Rankine and Brayton systems was also investigated. A target goal of 5 kg/kWe specific mass was deemed reasonable given either 1400 K potassium Rankine with 1500 K lithium-cooled reactors or 2000 K gas cooled reactors with Brayton conversion.

George, Jeffrey A.

Space nuclear power systems

Space nuclear power systems are considered for use in those particular spacecraft applications for which nuclear power systems offer unique advantages over solar and/or chemical space power systems. Both isotopic and reactor heated space electrical power units are described in an attempt to illustrate their operating characteristics, spacecraft integration aspects, and factory-to-end of mission operational considerations. The status of technology developments in nuclear power systems is presented. Some projections of those technologies are made to form a basis for the applications of space nuclear power systems to be expected over the next 10-15 years.

Carpenter, R. T.

The Satellite Nuclear Power Station - An option for future power generation.

A new concept in nuclear power generation is being explored which essentially eliminates major objections to nuclear power. The Satellite Nuclear Power Station, remotely operated in synchronous orbit, would transmit power safely to the ground by a microwave beam. Fuel reprocessing would take place in space and no radioactive materials would ever be returned to earth. Even the worst possible accident to such a plant should have negligible effect on the earth. An exploratory study of a satellite nuclear power station to provide 10,000 MWe to the earth has shown that the system could weigh about 20 million pounds and cost less than $1000/KWe. An advanced breeder reactor operating with an MHD power cycle could achieve an efficiency of about 50% with a 1100 K radiator temperature. If a hydrogen moderated gas core reactor is used, its breeding ratio of 1.10 would result in a fuel doubling time of a few years. A rotating fluidized bed or NERVA type reactor might also be used. The efficiency of power transmission from synchronous orbit would range from 70% to 80%.

Williams, J. R.

A look at the Soviet space nuclear power program

The Soviet Union has been flying nuclear power sources in space since about 1965. For the most part these nuclear power sources have been low-power nuclear reactors using a thermoelectric conversion principle. Recently the Soviet Union has flown two satellites using a higher power reactor that employs a thermionic conversion system. Reentry of two of the earlier reactors on board Cosmos 954 and Cosmos 1402 plus the recent potential accident involving Cosmos 1900 have focused world attention on Soviet usage of space nuclear power. Despite these problems the evidence points toward a continued Soviet usage of nuclear power sources in space.

Inductors

Thermophotovoltaics for In-Space Nuclear Power

In-space nuclear power systems are under consideration for missions that need lots of power. Recent work in Thermophotovoltaic (TPV) cells indicates that they may be a mass efficient option for converting a nuclear reactor’s thermal energy into electrical energy. This paper briefly trades TPV versus a Brayton Cycle in the context of a conceptual Earth-to-Mars transportation system. The selection of the heat engine primarily impacts the design of the nuclear reactor, power handling electronics, fluid loops, heat exchangers, and thermal radiator, so the impact to these subsystems is also considered. The mass and electrical power generation are the primary figures of merit compared between the two alternatives, and qualitative differences are discussed.

Nuclear

Thermophotovoltaics for In-Space Nuclear Power

In-space nuclear power systems are under consideration for missions that need lots of power. Recent work in Thermophotovoltaic (TPV) cells indicates that they may be a mass efficient option for converting a nuclear reactor’s thermal energy into electrical energy. This paper briefly trades TPV versus a Brayton Cycle in the context of a conceptual Earth-to-Mars transportation system. The selection of the heat engine primarily impacts the design of the nuclear reactor, power handling electronics, fluid loops, heat exchangers, and thermal radiator, so the impact to these subsystems is also considered. The mass and electrical power generation are the primary figures of merit compared between the two alternatives, and qualitative differences are discussed.

Nuclear

A Comparison of Energy Conversion Technologies for Space Nuclear Power Systems

A key element of space nuclear power systems is the energy conversion subsystem that converts the nuclear heat into electrical power. Nuclear systems provide a favorable option for missions that require long-duration power in hostile space environments where sunlight for solar power is absent or limited. There are two primary nuclear power technology options. Radioisotope Power System (RPS) utilize the natural decay heat from Pu238 to generate electric power levels up to about one kilowatt. Fission Power System (FPS) rely on a sustained fission reaction of U235 and offer the potential to supply electric power from kilowatts to megawatts. Example missions for nuclear power include Mars science rovers (e.g. Curiosity, Mars 2020), lunar and Mars surface landers ? including crewed missions, deep space planetary orbiters, Ocean World science landers, and robotic space probes that utilize nuclear electric propulsion. This paper examines the energy conversion technology options that can be used with RPS and FPS, and provides an assessment of their relative performance and technology readiness.

Mason, Lee S.

Comparison of Energy Conversion Technologies for Space Nuclear Power Systems

A key element of space nuclear power systems is the energy conversion subsystem that converts the nuclear heat into electrical power. Nuclear systems provide a favorable option for missions that require long-duration power in hostile space environments where sunlight for solar power is absent or limited. There are two primary nuclear power technology options: (1) radioisotope power systems (RPSs) utilize the natural decay heat from 238Pu to generate electric power levels up to about 1 kW and (2) fission power systems (FPSs) rely on a sustained fission reaction of 235U and offer the potential to supply electric power from kilowatts to megawatts. Example missions utilizing nuclear power include Mars science rovers (e.g., Curiosity, Mars 2020), lunar and Mars surface landers, crewed surface outposts, deep space planetary orbiters, Ocean World science landers, and robotic space probes that utilize nuclear electric propulsion. This report examines the energy conversion technology options that can be used with RPSs and FPSs, and provides an assessment of their relative performance.

Lee S Mason

Prevented Mortality and Greenhouse Gas Emissions From Historical and Projected Nuclear Power

In the aftermath of the March 2011 accident at Japan's Fukushima Daiichi nuclear power plant, the future contribution of nuclear power to the global energy supply has become somewhat uncertain. Because nuclear power is an abundant, low-carbon source of base-load power, it could make a large contribution to mitigation of global climate change and air pollution. Using historical production data, we calculate that global nuclear power has prevented an average of 1.84 million air pollution-related deaths and 64 gigatonnes of CO2-equivalent (GtCO2-eq) greenhouse gas (GHG) emissions that would have resulted from fossil fuel burning. On the basis of global projection data that take into account the effects of the Fukushima accident, we find that nuclear power could additionally prevent an average of 420 000−7.04 million deaths and 80−240 GtCO2-eq emissions due to fossil fuels by midcentury, depending on which fuel it replaces. By contrast, we assess that large-scale expansion of unconstrained natural gas use would not mitigate the climate problem and would cause far more deaths than expansion of nuclear power.

nuclear power plants

Solid-State Thermionic Nuclear Power for Megawatt Propulsion, Planetary Surface and Commercial Power Project

Thermionic (TI) power conversion is a promising technology first investigated for power conversion in the 1960's, and of renewed interest due to modern advances in nanotechnology, MEMS, materials and manufacturing. Benefits include high conversion efficiency (20%), static operation with no moving parts and potential for high reliability, greatly reduced plant complexity, and the potential for reduced development costs. Thermionic emission, credited to Edison in 1880, forms the basis of vacuum tubes and much of 20th century electronics. Heat can be converted into electricity when electrons emitted from a hot surface are collected across a small gap. For example, two "small" (6 kWe) Thermionic Space Reactors were flown by the USSR in 1987-88 for ocean radar reconnaissance. Higher powered Nuclear-Thermionic power systems driving Electric Propulsion (Q-thruster, VASIMR, etc.) may offer the breakthrough necessary for human Mars missions of < 1 yr round trip. Power generation on Earth could benefit from simpler, moe economical nuclear plants, and "topping" of more fuel and emission efficient fossil-fuel plants.

George, Jeffrey

Recent Advances in Nuclear Powered Electric Propulsion for Space Exploration

Nuclear and radioisotope powered electric thrusters are being developed as primary in-space propulsion systems for potential future robotic and piloted space missions. Possible applications for high power nuclear electric propulsion include orbit raising and maneuvering of large space platforms, lunar and Mars cargo transport, asteroid rendezvous and sample return, and robotic and piloted planetary missions, while lower power radioisotope electric propulsion could significantly enhance or enable some future robotic deep space science missions. This paper provides an overview of recent U.S. high power electric thruster research programs, describing the operating principles, challenges, and status of each technology. Mission analysis is presented that compares the benefits and performance of each thruster type for high priority NASA missions. The status of space nuclear power systems for high power electric propulsion is presented. The paper concludes with a discussion of power and thruster development strategies for future radioisotope electric propulsion systems,

Cassady, R. Joseph